Band sawing machine



July 22, 1958 R. CRANE ET AL BAND SAWING MACHINE 8 Sheets-Sheet 1 FiledDec. 24, 1956 July 22, 1958 R. L. CRANE ET AL 2,343,917

BAND SAWING MACHINE Filed Dec. 24, 1956 8 Sheets-Sheet 2 170174 2? I.[mm Jim W Wz/km July 22, 1958 R. L. CRANE ET AL BAND SAWING MACHINE 8Sheets-Sheet 3 Filed Dec. 24, 1956 10274 2 2! [may E Jamgs W Wz/lrm July22, 1958 R. L. CRANE ET AL 2,843,917

BAND SAWING MACHINE 8 Sheets-Sheet 5 Filed Dec. 24, 1956 July 22, 1958R. CRANE ET AL 2,843,917

BAND SAWING MACHINE Filed Dec. 24, 1956 1 8 Sheets-Sheet 6 July 22, 1958R. L. CRANE ET AL BAND SAWING MACHINE 8 Sheets-Sheet '7 Filed Dec. 24.1956 Zaharzl. [MM Jizzzgs W Ml/tw July 22, 1958 R. CRANE ET AL 2,843,917

BAND SAWING MACHINE Filed Dec. 24, 1956 s Sheets-Sheet 8 1 017:?! J. mm:Jam: 1 Iii/Av! United States Patent nnnn sawrno MACHINE Robert L. Craneand lames W. Wilkie, Hopkins, Minn, assignors to Continental Machines,Ina, Savage, Mrnn., a corporation of Minnesota Application December 24,1956, Serial No. 630,171

14' Claims. (El. li -6 This invention relates to improvements in machinetools on the order of that disclosed in the copending application ofRobert L. Crane, Serial No. 488,536 filed February 16, 1955, whereinwork is performed on large and heavy work pieces while the latter areheld stationary and the machine is moved bodily relative thereto so asto feed its work performing element into the work piece' The machinetool of said application is a filing machine especially adapted for usein filing dies and other work pieces that are too large and. heavy to bemoved about in order to present selected areas thereof to the fileelement. In general, it comprises a C-shaped carrier which is mountedover a horizontal supporting surface for substantially free movement inall directions parallel to said surface, and it is provided with avertically reciprocable file element mounted in suitable rotary guidemembers on the arms of the C-shaped carrier with the file elementspanning the working space between the carrier arms. The file element isfreely slidably but nonrotatably received in the guide members and thelatter are constrained to rotate in unison and in the same direction sothat the operator of the machine may turn the file element in its pathof travel to present its abrading surface to different areas of the workpiece merely by imparting rotation to the guide members. The operatoralso manually moves the C-shaped carrier bodily to effect feeding of thefile element into the work piece, and a single handle member readilyaccessible to the operator is connected to one of the rotary guidemembers to facilitate both guiding and feeding of the file element intothe work.

Despite the fact that the C-shaped carrier was supported from astationary pedestal by means of a free swinging double hinge mounting toenable it to be moved in all directions parallel to the supportingsurface with a minimum of effort, it nevertheless required a skilledoperator to coordinate two motions, namely, swinging of the carrierbodily along with turning of the tool element relative to the carrier,while also controlling his application of tool feeding force to thecarrier in order to achieve efficient and accurate machining. Thus forexample it was quite difiicult for all except the more highly skilledand experienced operators to utilize the machine of the aforesaidcopending application to its best advantage, especially if there was anytendency on the part of an operator maintaining accuracy foremost in hismind to ease up or even momentarily forget to move or swing the carrierin the direction in which he had turned the file element, and to applyto the carrier the force necessary for efficient filing.

It is the primary purpose of this invention, therefore, to provide amachine tool of the character described having power operated means forimparting swinging and tool feeding motion to the carrier, and whereinsuch swinging motion of the carrier is automatically coordinated withmanual turning of the tool element relative to the carrier.

Another purpose of this invention resides in the provision of poweroperated means of the character described ICQ 2,843,917 Patented July22, 1958 which is applicable to the C-shaped carriers of sawing as wellas filing machines of the type described.

More specifically it is an object of this invention to provide a machinetool such as a sawing or filing machine with a guide wheel driven by atorque motor and mounted on the bottom of the G-shaped carrier of themachine for tractive engagement with the supporting surface over whichthe carrier moves and constrained to swiveling motion about the commonvertical axis of the rotary tool guiding members, in unison withrotation of said tool guiding members, upon turning of the latter by theoperator.

In the case of the band sawing machine herein disclosed, it will beunderstood that the tool. element is an endless saw band trained aboutsuitable drive and idler pulleys on the C-shaped carrier with onestretch thereof constrained to continuous travel downwardly along avertical path through the working space between the arms of the carrierby means of spaced upper and lower tool guiding members similar to thoseemployed in the filing machine of the aforesaid copending application.These tool guiding members are also mounted on the carrier arms forrotation in unison in opposite directions about a common vertical axiscoincident with the cutting edge of that stretch of the saw band whichextends between the guide members, and the saw band, of course, isfreely slidably but nonrotatably received in the guide members so thatrotation imparted manually thereto effects turning of the band bytwisting that stretch thereof which extends between the guide members.

Still another object of this invention resides in the provision of amachine tool of the character described with means for readilyreleasably maintaining the power driven guide or feed Wheel in tractiveengagement with the supporting surface over which the tool carrier isdriven by the wheel.

In this respect it is a more specific object of the invention to mountthe guide or feed wheel on the tool carrier of a machine tool of thecharacter described by means of a spindle which provides for swivelingmotion of the wheel about a vertical 'aXis common to that about whichthe tool guiding members rotate, and which spindle comprises the plungerof a double acting fluid pressure operated cylinder so that pressureexerted in one end of the cylinder causes the guide or feed wheel to bemaintained in tractive engagement with the supporting surface whilepressure exerted in the other end of the cylinder effects retraction ofthe wheel away from the supporting surface to permit the carrier to bequickly moved manually.

Still another object of this invention resides in the provision of amachine tool of the character described wherein the power driven guidewheel may be automatically turned about its vertical axis to change thedirection of tool feeding motion of the tool carrier by a motor at thedictation of tracer means which follows an edge portion on a templatehaving the outline of the desired cut to be made in the work piece.

With the above and other objects .in view, which will appear as thedescription proceeds, this invention resides in the novel construction,combination and arrangement of parts substantially as hereinafterdescribed and more particularly defined by the appended claims, it beingunderstood that such changes in the precise embodiment of thehereindisclosed invention may be made as come within the scope of theclaims.

The accompanying drawings illustrate several complete examples of thephysical embodiments of the invention constructed according to the bestmodes so far devised for the practical application of the principlesthereof, and in which:

Figure 1 is a side elevational view of a band sawing machine embodyingthe principles of this invention, portions thereof being broken away toillustrate details of construction;

Figure 2 is a plan view of the machine shown in Figure 1;

Figure 3 is a more or less diagrammatic perspective view showing themanner in which the power operated guide wheel is constrained to turnwith the saw band guides;

Figure 4 is an enlargement of the band guiding and power feedingmechanism seen in Figure 1;

Figure 5 is a vertical sectional view through the lower band guidingmember, taken along the plane of the line 5-5 in Figure 4;

Figure 6 is a vertical sectional view through the upper band guidingmember, taken along the plane of the line 66 in Figure 4;

Figure 7 is a vertical sectional view through the guide wheel mechanismand the means which mounts the same, taken along the plane of the line7-7 in Figure 4;

Figure 8 is a vertical sectional view taken through Figure 7 along theplane of the line 8-8;

Figure 9 is a diagrammatic perspective view illustrating the controlmeans for starting and stopping the torque motor for the guide wheel;

Figure 10 is a perspective view similar to Figure 3 but illustrating amodified embodiment of the invention wherein the guide wheel isconstrained to follow a template.

Figure 11 is a detail sectional view showing the manner in which theguide wheel is engaged with the template shown in Figure 10;

Figure 12 is a perspective view similar to Figure 3 but illustratinganother manner in which a template may be used to control the directionof feeding motion of the tool carrier;

Figure 13 is a diagrammatic view of a portion of the template followingmechanism shown in Figure 12, and illustrating how a hydraulic motor forturning the guide wheel on its vertical axis may be governed thereby;and

Figure 14 is a fragmentary perspective view showing another embodimentof the invention.

Referring now particularly to the accompanying drawings in which likereference characters have been applied to like parts throughout theseveral views, the machine tool of this invention is shown as comprisinga band saw, although it will be understood that the invention is equallywell applicable to filing machines of the type disclosed in thecopending application of Robert L. Crane, Serial No. 488,536, filedFebruary 16, 1955. The main components of the band saw are substantiallyidentical to those of the filing machine of the aforesaid copendingapplication, and comprise a fixed pedestal A; an arm B hingedlyconnected to and supported from the pedestal for free swinging motion inopposite directions about a vertical axis; a C-shaped rigid frame orcarrier C hinged to and supported from the outer end of the arm B forswinging motion in opposite directions about a vertical axis; a toolelement D, which in this case is an endless saw band; and a poweroperated guide or feed wheel E.

The pedestal A, of course, is suitably anchored to a base or foundationhaving a horizontal supporting surface S, and the axes of the doublehinged connection between the carrier C and the pedestal are exactlyvertical. By reason of this double hinged connection, therefore, thecarrier C may be swung in all directions relative to the pedestal,parallel with the horizontal supporting surface S, and the wide area inwhich work may be performed by its tool element D upon a Work piece Wheld in a stationary position by any suitable means, is diagrammaticallyillustrated in Figure 2.

As is more or less conventional in sawing machines having a continuoussaw band, the tool element or endless saw band D is trained over pairsof vertically aligned inner and outer band wheels or pulleys P on thecarrier so arranged that the cutting stretch of the band, which extendsbetween the outermost pair of pulleys, travels downwardly in a verticalpath through the working zone defined by the space between thehorizontal upper and lower arms 10 and 11, respectively, of the C-shapedcarrier. One of the pulleys P, preferably that which is carried by theouter end portion of the lower arm 11 of the C-shaped carrier, isconnected with a motor 12, and the other pulleys are idlers, but one ofthese idler pulleys is journalled in a slidably mounted block for bandtensioning adjustment by any suitable means such as the hand screw shownin Figure 1 or the hydraulic cylinder shown in Patent No. 2,607,373,which points out that the tension maintained on the band must becorrelated to the width of the band.

The cutting stretch of the saw band is constrained to linear verticaltravel through the working zone by means of vertically spaced upper andlower guide members 14 and 15 respectively mounted on the upper andlower arms of the carrier.

Each of these guide members comprises a bearing housing 16 having a tube17 constrained to rotation on a vertical axis therein, and a sleeve 18within and projecting entirely through the tube with the sleeve splinedthereto as at 19. The bearing housings are so mounted on the outer endsof the upper and lower carrier arms as to hold the tubes and theirsleeves on a common vertical axis which lies in the plane of the cuttingstretch of the saw band, and in most instances is coincident with thetoothed edge 20 thereof.

The cutting stretch of the saw band, of course, extends downwardlythrough the sleeves of both the upper and lower guide members to beslidably but nonrotatably received between the jaws of saw guides 21carried by collars 22 fixed to the adjacent ends of the upper and lowersleeves 18. While the sleeves are constrained to rotate with the tubes17, their splined connections with the tubes permit them to be adjustedvertically, relative to the carrier arms, and they may be held in anydesired position of vertical adjustment by means of annular clampingmembers 23 on the tubes through which the adjacent end portions of thesleeves project. A screw 24 on each of the clamping members, whenloosened, provides for such up and down adjustment of the sleeves withrespect to their tubes 17, but the sleeves are held against all butrotary motion with their tubes when the screws are tightened.

As in the aforesaid copending application the tubular members of theupper and lower guides are constrained to turn in unison, and for thispurpose they are drivingly connected together. This driving connectioncomprises a vertical shaft 25 rotatably mounted in a vertical positionin the bak of the C-shaped carrier, and chain and sprocket connections27 between the tubes 17 and the shaft. Manually operable handle means 28mounted upon the clamp 23 of the upper guide member provides for thetransmission of rotation to the upper and lower guide members to thuseffect twisting of the cutting stretch of the saw band which extendsbetween the guides 21, relative to the carrier, so as to enable turningof the band as required when following an irregular reference linedelineated on a Work piece W held in a stationary position between thearms of the carrier. The handle means 28, of course, also enables theoperator to move the entire carrier C on its double hinged support whenfeeding motion of the saw band into the work is to be imparted to thecarrier manually. While the handle means has been illustrated ascomprising a pair of diametrically opposite arms having grips 29 ontheir outer ends, it will be appreciated that a ring or wheel 29 may besubstituted for the grips as shown in Figure 14.

According to this invention, tool feeding motion is d imparted to thecarrier by means of a power driven feed or guide wheel 30 carried by thelower arm 11 of the carrier and having its periphery in tractiveengagement with the supporting surface S over which the carrier moves.

The guide or feed wheel is fixed on a horizontal axle 31, the ends ofwhich are journaled in suitable hearings on a wheel supporting member 32having an electric torque motor 33 mounted on one side thereof. Themotor is drivingly connected with the axle by means which includes atransmission 34 and gears 35 on the output shaft of the transmission andon one end of the axle.

The wheel supporting member 32 is mounted upon the lower end portion ofa vertical spindle 37, with the wheel supporting member constrained torotation about the axis of the spindle but prevented from axial motionrelative thereto. As seen best in Figure 7, the spindle is hollow andcomprises the plunger of a double acting fluid pressure operatedcylinder 39 secured in the lower arm 11 of the carrier with the plungeror spindle coaxial with the upper and lower guide members for the sawband.

Mounted on the plunger or spindle 37 inside the cylinder 39 is a pistonl-ti, so that when fluid under pressure is admitted into the cylinder atone side or the other of the piston the plunger or spindle 37 will beraised or lowered to carry with it the wheel supporting member 32 andthe feed or guide Wheel 30 thereon. Thus, if fluid under pressure isadmitted into the upper end portion of the cylinder to the space abovethe piston 40, as through a fluid line 41, the piston will be forceddownwardly to tractively engage the periphery of the feed or guide wheelwith the supporting surface S. In the event it is desired to lift thefeed or guide wheel off of the supporting surface to facilitate manualswinging of the carrier from one location to another, fluid underpressure is introduced through a second fluid line 42 into the lower endportion of the cylinder to the space below the piston 40 to cause thewheel to be carried upwardly away from the supporting surface. Normally,however, fluid pressure is maintained in the upper end portion of thecylinder so as to assure good tractive engagement between the peripheryof the feed or guide wheel 30 and the supporting surface.

An important feature of the invention resides in the fact that the wheelsupporting member is constrained to rotate in unison with the guidemembers for the cutting stretch of the saw band. For this purpose thewheel supporting member 32 has a sprocket 44 fixed thereto opposite asprocket 45 on the lower end of the vertical shaft 25, and a chain 46 istrained over the sprockets 44 and 45.

It is important to note, however, that the horizontal axis about whichthe feed or guide wheel rotates is intersected by the common axis of theguide members and the spindle 3'7, and since this axis lies in the planeof the cutting stretch of the saw band and may, for instance, becoincident with the cutting edge of the saw band, it will be apparentthat whenever the guide members are rotated manually to cause the saw tofollow an irregular out in a work piece, the cutting stretch of the sawband will be twisted in its vertical path simultaneously with turning ofthe feed or guide wheel 30 on its spindle 37, in the same direction thatthe band is twisted. The motor 33 for the feed or guide wheel, ofcourse, will impart rotation to the wheel in the direction to effect thenecessary tool feeding force and motion of the G-shaped carrier.

With this arrangement, an operator of the sawing machine need onlyconcentrate on turning or twisting the cutting stretch of the saw bandin its vertical path, relative to the carrier C, during the cutting ofan irregular course through a Work piece W, and that as a consequence ofmanual rotation of the guide members to twist the band, the power drivenfeed or guide wheel will be turned about its vertical axis in the samedirection as the saw band and will impart tool feeding motion to thecarrier d 7 along a path which is parallel to the opposite faces of thecutting stretch of the band. Moreover, inasmuch as the prime mover forthe feed or guide wheel is a torque motor, it will be appreciated thatit will tend at all times to maintain the cutting edge of the sawengaged with the work piece with a force which is constant andindependent of the speed of feed motion.

Attention is directed to the fact that since the spindle or plunger 37upon which the feed or guide wheel swivels is hollow, it enables theelectrical conductor 48 by which energizing current is supplied to themotor 33 to be led downwardly therethrough and into the wheel supportingmember 32, with the conductor located on the vertical axis about whichthe wheel swivels. The conductor 48 is preferably in the form of anelongated closely coiled helix extending coaxially through the interiorof the spindle so that the feed or guide wheel and the wheel supportingmember 32 upon which it is mounted may turn freely relative to thespindle 37 without any danger of damaging the electrical conductor.

Also as seen best in Figure 8, the helically coiled conductor 48surrounds a tube 50 having its upper end projecting from the spindle orplunger of the fluid pressure operated cylinder and provided with anelbow fitting 51 by which it is connectible with a source of air underpressure. A nozzle 52 on the lower end of the tube, extending downwardlyand forwardly ahead of the periphery of the guide wheel, enables a blastof air to be directed against the supporting surface S so as to blowaside chips of metal or other particles from the supporting surfacebefore the guide wheel travels thereover.

Electrical control instrumentalities, generally desig nated 53 inFigures 1 and 14, govern the speed and operativeness of the torque motor33. These instrumentalities are mounted on a control panel fixed to theouter end of the upper arm 10 where their actuators are readilyaccessible to an operator of the saw, and these instrumentalitiesinclude an on-olf switch, and a variable resistor by which the voltageto the torque motor may be regulated.

From the description thus far, it will be apparent that the feed orguide wheel 30 will be bodily moved toward tractive engagement with thesupporting surface whenever the fluid line 41 leading to the upper endof the cylinder 39 is communicated with a source of fluid under pressureand the fluid in the lower end of the cylinder is free to exhaustthrough the fluid line 42; and that the wheel will be bodily moved to aninoperative position spaced from the supporting surface whenever thefluid line 42 is communicated with the source of fluid under pressureand the fluid in the upper end of the cylinder is free to exhaustthrough the fluid line 41. Suitable instrumentalities govern theconnection of the fluid lines 41 and 42 with the source, of fluid underpressure, and in the present case these instrumentalities comprise asolenoid. actuated valve, not'shown, and a double throw switch 54 whichcontrols the valve. This switch is preferably mounted in the upper arm10 of the carrier alongside the bearing housing of the upper saw guidemember 14, and is actuated by a lever 56 pivotally mounted on one of thegrips 29 of the handle means 28 so as to be readily actuatable by anoperator.

The lever 56 is connected with the actuating arm 55 of the switchthrough a suitable motion transmitting connection including a Bowdenwire 58, a ring 60 overlying and pivotally connected as at 61 to the topof the handlemember 28, and a pin 63; the Bowden wire being con nectedto the ring and the lever. Therefore, when the operator actuates thelever in one direction the ring 60 is tilted upwardly on its hinge 61,and such tilting motion of the ring is translated into switch actuatingmotion of the switch arm 55 by means of the pin 63. Actuation of theswitch in this manner efifects connection of the lower end of thecylinder 39 with the source of fluid under pressure to cause the feed orguide wheel 30 to be lifted ofi of the supporting surface to thus enablethe operator to swing the C-shaped carrier freely in any direction. Whenthe operator moves the control lever 56 in the opposite direction, theswitch 54 returns to its normal position elfecting connection of theupper end of the cylinder 39 with the source of fluid under pressure,and causing the feed or guide wheel to resume its normal positiontractively engaging the supporting surface.-

Obviously, if desired, the control valve (not shown) may be operateddirectly by the pin 63 or in any other manner as a consequence ofswinging the control lever 56, in which event the switch 54 would not beneeded.

With the apparatus described it will be apparent that a sawing operationcarried out in a work piece W along an irregular layout line requiresthe presence of an operator to guide the cutting stretch of the saw bandthrough the work, by turning the handle means to twist the cuttingstretch of the saw band as required. The operator, however, need not beconcerned with the bodily swinging motion of the carrier incorrespondence with such twisting of the saw hand, nor need the operatorgive any attention to the maintenance of the required feed pressurebetween the cutting edge of the saw and the work. These two functionsare carried out automatically by the "feed or guide wheel and its torquernotor.

If desired, a template 66 having the shape of the cut to be made in thework piece may be employed in the manner shown in Figure to guide thewheel and thereby effect turning of the cutting stretch of the saw bandin its vertical path as required to produce the desired cut in the workpiece entirely aiutornatically. As shown in Figure 10 the template 66may be secured to the supporting surface S beneath the lower arm 11 ofthe carrier and it preferably has a groove 67 in its upper surface toprovide a track in which the peripheral portion of the feed or guidewheel 30 travels.

Depending upon the shape of the track, therefore, the Wheel 30 will beturned about its vertical axis as it travels along the track, and all ofthe swiveling motion which is thus imparted to the feed or guide wheelwill likewise be transmitted to the saw guides 21 to effect twisting ofthe cutting stretch of the saw in the same direction that the feed orguide wheel swivels.

When an irregular cutout is to be made in the body of the work piece,however, it will be appreciated that a small hole 69 is first drilledinside the layout line delineated on the upper surface of the work pieceto enable a proper length of saw band to be passed therethrough. Theends of the saw are then welded together to form a continuous bandaround the pulleys P, and the operator must manually direct the cuttingoperation to start the cut along the layout line. Thereafter, the guidewheel may be engaged with the template 66 to cause the remainder of thesawing operation to be carried out automatically.

Automatic operation of the sawing machine can also be effected in themanner disclosed in Figures 12 and 13 wherein swiveling motion isimparted to the guide wheel 30 about its vertical axis as a consequenceof the engagement of a tiltable tracer finger 71 with the edge 72 of atemplate 73 mounted above the upper arm 10 of the carrier. In this casethe tilting of the tracer finger effects sliding motion of the plunger74 of a hydraulic control valve 75 which governs the flow of fluid underpressure to a reversible hydraulic motor 76. This hydraulic motor 76 hasa drive sprocket 77 thereon connected by means of a chain 78 with asprocket 79 on the upper end of the vertical shaft 25' so as todrivingly connect the hydraulic motor with the band guide members andthe guide wheel 30.

As diagrammatically shown in Figure 13, the plunger 7 4 is biasedupwardly toward engagement with the lower end'of the tracer finger, andit controls communication between an inlet port in the valve bodyconnecting with a supply line 81, and a pair of motor ports in the valvebody connecting with motor lines 82 and 83. Thus, with the tracer fingerin a tilted position as shown, the plunger is held thereby in a positionblocking both motor ports and the guide wheel 30 will feed the machinealong a straight line path until the tilt angle of the tracer finger ischanged by the template.

Thus, for example, if the template acts on the tracer finger to tilt itfarther out of a vertical position, the finger slides the plungerdownwardly to connect the motor line 32 with the supply line 81 foroperation of the hydraulic motor in one direction. Fluid exhausting fromthe motor is returned to the valve through the other motor line 83 andflows to a sump through one of two return lines 84. The hydraulic motor,of course, is driven in said one di rection at a speed depending uponthe rate at which fluid is allowed to pass into the line 82 by theplunger, and such operation of the motor effects swiveling of the guideWheel in unison with twisting of the cutting stretch of the saw band inthe proper direction as determined by the template.

The guide wheel and the saw band are turned in unison in the oppositedirection by the hydraulic motor in the event the template causes thetracer finger to assume a position of less tilt than is shown in Figure13. In that case, the valve plunger connects the motor line 83 with thesupply line, and the motor line 82 with the other return line 84, toreverse the hydraulic motor.

From the foregoing description taken together with the accompanyingdrawings it will be readily apparent to those skilled in the art thatthis invention materially improves the operation of machine tools suchas sawing and filing machines in that it minimizes the amount ofattention which an operator must give to the machine in order to performwork, such as cutting or abrading, along a predetermined reference lineon a Work piece.

What is claimed as our invention is:

l. A machine tool of the type comprising a (t-shaped carrier havingspaced apart upper and lower arms defining a working zone therebetween,means mounting the carrier over a supporting surface for horizontalmovement in all directions parallel to said surface so that work may beperformed by the machine tool as a consequence of movement of thecarrier relative to a work piece in the working zone, and a power driventool element comprising an endless saw band mounted on the carrier withone stretch thereof constrained to linear travel along a vertical paththrough the working zone, characterized by: upper and lower saw guidesin which the saw band is slidably but nonrotatably received; meansmounting one of said guides on each arm of the carrier for rotation on avertical axis coincident with the cutting edge of said stretch of thesaw band; handle means mounted on the carrier for rotation in oppositedirections; means drivingly connecting said handle means with both sawguides so that the latter may be rotated simultaneously in the samedirection by the handle means to effect twisting of that portion of thehand between the guides and cutting by the saw band along an irregularline; and power operated means for propelling the carrier in a toolfeeding direction relative to a work piece between the carrier arms,comprising a traction wheel on the carrier with its periphery intractive engagement with the supporting surface, means mounting thetraction wheel on the carrier for swiveling movement coaxially of thesaw guides and for rotation about a horizontal axis intersecting theswivel axis of the wheel, means drivingly connecting the traction wheelwith said saw guides so as to constrain the guide wheel to swivelingmotion in unison with rotation of the saw guides and in the samedirection that the saw guides are rotated by the handle means, and amotor drivingly connected with said traction wheel for rotating the sameabout its horizontal axis.

2. The machine tool set forth in claim 1 further characterized by thefact that said handle means is mounted on and drivingly connected withthe upper one of said saw guides.

3. A machine tool of the type comprising a C-shaped carrier havingspaced apart upper and lower arms defining a working zone therebetween,with a power driven tool element thereon constrained to travel linearlyalong a vertical path through the working zone, and wherein the carrieris mounted over a horizontal supporting surface for movement in alldirections parallel to said surface so that work is performed by thetool element as a consequence of movement of the carrier relative to awork piece in the working zone, characterized by: the fact that the toolelement is an endless saw band having one stretch constrained to travelalong said vertical path; the provision of upper and lower guides forthe saw band mounted on the carrier arms and constrained to rotate inunison on a common vertical axis coincident with the cutting edge ofsaid stretch of the saw band, said guides being slidably butnonrotatably connected to the saw band so that rotation of the guidestwists that portion of the hand between them relative to the carrier;the provision of a power driven traction wheel on the carrier having itsperiphery in tractive engagement with the supporting surface; theprovision of means mounting the traction Wheel for bodily turningmovement in unison with and in the same direction as the saw guides,about a vertical axis coincident with the cutting edge of said stretchof the saw band and intersecting the axis of wheel rotation; and theprovision of handle means mounted on the carrier for imparting rotarymotion in unison to the saw guides and the traction wheel.

4. In a machine tool, the combination of: an upright C-shaped framehaving spaced upper and lower arms between which work to be acted uponmay be received; means mounting the frame for bodily horizontal toolfeeding movement in all directions over an upwardly facing supportingsurface; an elongated power driven tool element on the frame extendingvertically. across the space between its arms, said tool element havinga laterally facing. cutting edge extending along the length thereof sothat the tool element performs its cutting function by lengthwisemovement thereof relative to the frame as tool feeding motion isimparted to the frame, provided that the cutting edge of the toolelement faces in the direction of such tool feeding motion; meansconstraining the tool element to travel along a vertical path acrosssaid space comprising upper and lower guides in which the tool elementis non-rotatably received; means mounting said guides on the arms of theframe for rotation on a vertical axis coincident with said path; meansconnecting said guides to constrain the same to rotate in unison wherebyrotation of the guides effects turning of the tool element in its pathrelative to the frame to provide for orientation of the tool element toface its cutting edge in whatever direction tool feeding motion must beimparted to the frame to effect cutting of a selected portion of thework; a wheel supporting member mounted on the lower arm of the framefor turning motion about a vertical axis common to that of said guides;power operated means for imparting tool feeding motion to the frame inthe direction in which the cutting edge of the tool element facescomprising a traction wheel mounted on said wheel supporting member forbodily turning motion therewith and for rotation about a horizontal axiswith the periphery of said wheel in position to have tractive engagementwith an upwardly facing supporting surface beneath the lower arm of theframe; means connecting the wheel supporting member with said guides toconstrain the wheel supporting member and the traction wheel thereon toturn in unison with said guides about the common vertical axis thereof,said last named means holding the traction wheel with its axis parallelto the cutting edge of the tool element so that regardless of theorientation of the tool element the traction wheel is alwaysin positionto impart tool feeding motion to the frame in the proper direction; andcontrol means operatively connected with the rotatable guides to effectrotation of the guides and thus provide for any desired orientation ofthe tool element and traction wheel.

5. The machine tool set forth in claim 4 wherein the mounting for thewheel supporting member comprises a vertically disposed hollow shaftmounted on the frame in alignment with said path of the too-l elementand having the wheel supporting member journalled on its lower endportion; and further characterized by the fact that the power operatedmeans for imparting tool feeding motion to the frame includes anelectric motor mounted on the wheel supporting member and drivinglyconnected to the traction wheel; and by the provision of means forcontrolling the motor including a helically coiled insulated conductorextending longtudinally through the hollow interior of the shaft.

6. The machine tool set forth in claim 4, wherein said last named meanscomprises a template having a grooved track in which the guide wheelrides, said track conforming to the outline of the cut to be made in awork piece by the saw.

7. The machine tool set forth in claim 4, wherein said last named meanscomprises a reversible motor drivingly connected with the guide wheel toimpart turning motion thereto in one direction or the other about itsvertical axis, a tracer device adapted to engage an edge of a templateshaped to correspond to the cut to be made in a work piece by the saw,and motor control means operated by said tracer.

8. The machine tool set forth in claim 7, wherein said reversible motoris of the hydraulic type, and wherein said motor control means comprisesa reversing and metering valve element actuated by said tracer device,for governing the operation of the hydraulic motor.

9. In a band saw having a C-shaped frame and an endless saw band mountedthereon and driven to move with one substantially straight stretchthereof travelling across the space between the arms of the frame to sawthrough work received between the arms, and having means to maintain thesaw band under tension; a pair of guide members, one of which is mountedin each arm of the frame for free and unrestricted rotation about anaxis common to that of the other member, and for coaction with saidstretch of the band at locations spaced apart lengthwise thereof andfrom the ends of said stretch so that that portion of the stretch whichextends between the guide members constitutes the work performingportion of the band; means on the rotatable guide members slidinglygripping the opposite faces of the saw band whereby rotation of theguide members in unison about their common axis twists the workperforming portion of the saw band therebetween relative to the endportions of said stretch and to the frame to thereby provide fororientation of said work performing portion of the saw band as requiredto effect sawing along an irregular contour line upon relative feedmotion between the frame and a work piece in position between the guidemembers; manually actuatable handle means mounted on the frame for backand forth movement relative to the frame; and means providing motiontransmitting driving connections between the handle means and saidrotatable members whereby actuation of the handle means is translatedinto rotation of the rotatable guide members in unison and twisting ofthe work performing portion of the band relative to the frame.

10. The band saw set forth in claim 9 wherein the work performingportion of the saw band is disposed vertically and the frame is movablehorizontally in all directions over an upwardly facing supportingsurface, relative to a work piece to be sawed, to enable the workperforming portion of the saw band to be brought into engagement withdifferent selected areas of the work piece without having to move thework, and further characterized by: the provision of steerable powerdriven means having tractive engagement with said upwardly facingsupporting surface for imparting feed motion to the frame in a directionto engage the cutting edge of said work performing portion of the sawband with work to be sawed; and means connecting the handle means withsaid steerable power driven means whereby steering motion is imparted tothe latter in synchronization with twisting of the work performingportion of the saw band by the handle means to assure feeding of the sawband into the work in the desired direction.

11. The band saw set forth in claim 9 further characterized by: meansmounting the frame for free horizontal movement in all directions overan upwardly facing supporting surface, and with the work perform ingportion of the saw band disposed vertically; a traction wheel; meansmounting the traction wheel on the frame with its axis horizontal andfor bodily swiveling motion about the common axis of said rotatableguide members, and with the wheel disposed to have tractive engagementwith said supporting surface; and means drivingly conmeeting thetraction Wheel with the rotatable guide members, with the axis of wheelrotation normal to the faces of the work performing portion of the sawband, so that the traction wheel is constrained to swivel bodily withthe work performing portion of the saw band as it is twisted by therotatable guide members to thus at all times maintain the axis ofrotation of the traction wheel normal to the faces of the workperforming portion of the saw band; and a motor drivingly connected withthe traction wheel to rotate the same on its horizontal axis in adirection to impart feed motion to the frame and thereby efiect propersawing engagement between the cutting edge of said work performingportion of the saw band and the work.

12. In a band saw having a C-shaped frame and an endless saw bandmounted thereon and driven to move with one substantially straightstretch thereof travelling across the space between the arms of theframe, and having means to maintain the saw band under tension; coaxialtubular members encircling said stretch of the band at locations spacedapart lengthwise thereof and from the ends of said stretch, the portionof the stretch which extends between said tubular members being the workperforming portion of the band; means freely rotatably butnon-longitudinally movably mounting the tubular members in the arms ofthe frame for unrestricted rotation about their common axis; meanscarried by said tubular members to turn therewith and having jawsthereon slidingly gripping the opposite faces of the saw band so thatrotation of the tubular members in unison about their common axisprovides for twisting of the work performing portion of the saw bandrelative to the end portions of said stretch of the band and to theframe and orientation of the work performing portion of the saw band asrequired to effect sawing along an irregular contour line upon relativefeed motion between the frame and a work piece in position between thetubular members; means connecting said tubular members to constrain thesame to rotate in the same direction and in unison; and handle means onone of said rotatable tubular members whereby both of the tubularmembers may be rotated in unison.

1 3. The band saw set forth in claim 12 further characterized by theprovision of means mounting the frame for horizontal motion in alldirections, and with the work performing portion of the saw banddisposed vertically.

14. A machine tool of the type comprising a C-shaped carrier mountedover a supporting surface for horizontal movement in all directionsparallel to said surface, with a power driven tool element thereonhaving a work performing portion constrained to travel linearly along avertical path through a working zone between the arms of the carrier,characterized by: spaced tool guiding members which are mounted on thecarrier to rotate about a fixed common vertical axis coincident with thework performing portion of the tool element and are nonrotatablyconnected with the tool element so that the work performing portion ofthe tool element may be turned in its path by rotation of the toolguiding members in unison; power operated means for imparting horizontaltool feeding motion to the carrier, comprising means on the lowerportion of the carrier providing a double acting hydraulic cylinderhaving a piston rod reciprocable lengthwise on a vertical axiscoincident with the work performing portion of the tool element andprojecting downwarly from the cylinder toward the supporting surface; awheel supporting member mounted on the lower end portion of the pistonrod for rotation about the axis thereof but constrained to move up anddown with the piston rod during operation of the cylinder; a tractionwheel carried by the wheel suporting member for rotation on a horizontalaxis intersected by the axis of the piston rod and to turn bodily withthe wheel supporting member about the axis of the piston rod, saidtraction wheel being tractively engageable with the supporting surface;means for imparting such turning motion to the wheel supporting memberand the traction wheel thereon, including handle means drivinglyconnected with the wheel supporting member and with the tool guidingmembers so that the latter turn in unison with one another and with thetraction wheel; and a motor carried by the wheel supporting member andconnected with the traction wheel to impart rotation to the wheel aboutits horizontal axis, whereby the carrier may be moved horizontally in adirection under the control of the handle means to feed the workperforming portion of the tool element into a work piece in the workingzone, as a consequence of operation of the motor whenever fluid underpressure is admitted into said hydraulic cylinder to elfect downwardextension of the piston rod and tractive engagement of the tractionwheel with the supporting surface over which the carrier moves.

References Cited in the file of this patent UNITED STATES PATENTS2,693,737 Smith Nov. 9, 1954 2,705,510 Stocke Apr. 5, 1955 2,774,131Crane Dec. 18, 1956

